I peer through the window beside me. Bright blue-green sea below, such a vivid aquamarine that unless you saw it with your own eyes you wouldn’t believe it could actually exist in nature. Little white flecks dance across the azure blue, waves tossed up by the wake of the occasional boat. And then the deep aquamarine fades to a lighter blue as the water becomes more shallow; the coast comes into view. It’s my first glimpse of Italy, and it takes my breath away. It’s the start of July, full summer, and the sea and land are bathed in dazzling golden sunshine. I can see a marina along the coastline, tiny dots that must be fishing boats and yachts moored in an inlet. The seashore is the color of pale terra-cotta, but beyond it, beyond the miniature red roofs of the buildings that cluster around it, there’s rich green marshland. I know (from the in-flight magazine, not a more impressive source) that the Leaning Tower of Pisa stands in the Field of Miracles, and I squint, trying as hard as I can to make out a white pillar on a bed of green grass, but no luck.

Italy! My anticipation is intensifying so powerfully that I’m breathless. My mum says that when I was a little girl, I would get so excited at the prospect of a treat that I would barely be able to breathe; I’d rock back and forth, hyperventilating, making little gasping noises, eyes like saucers, mouth open. I twist away from the window, focusing on the gray marled fabric of the seatback in front of me, trying to calm the frantic pounding of my heart.

Because I left my mum behind. For two whole months. We’ve never been apart for that long, and I don’t know how she’s going to manage.

Even worse, I’m secretly, shamefully, glad. Glad to be leaving my mum, to be free for maybe the first time ever in my life. To be alone, without her always there, able to work out who I am in the space her absence will give me. Though I’m sitting in a cramped airline seat, arms tucked into my sides so I don’t accidentally whack my neighbor, I feel as if I have more space to breathe than ever before.

Maybe that’s how it always works; maybe you never realize how squashed in you’ve been until the restrictions vanish, and you can finally stretch out your arms. I feel as if I could whirl around again and again.

I should be in pieces about leaving Mum. I must be a really bad daughter.

I fumble for my phone, then remember I can’t turn it on midair. So I slip my laptop out of my bag for a brief moment and open it up; I’ve saved the photo of the portrait on it as well, just in case I lose my phone.

I click to open the picture, and get the same shock I always do as it comes up onscreen. I stare at myself, at hair decorated with pearls, at a green taffeta dress, my eyes looking back at me, and I know that I’ve done the right thing in leaving my mother behind to come on this quest to find out where I come from. And why on earth this girl from eighteenth-century Italy is my mirror image.

Because as I snap my laptop shut, I know that anyone who saw a resemblance like this would move heaven and earth to find out the reason behind it.

Ever since I saw the portrait in Sir John Soane’s Museum, I plotted and schemed and strategized so successfully that I surprised myself with the sheer extent of my capacity for covert action. The first thing I did was drop the name of the Castello di Vesperi into conversation with my mum.

Faux-casually, of course. I’ve just done my final A‑level exams--English, French, and art history--and the plan is for me to study art history at Cambridge University, if they let me in. In the autumn, I’ll sit the Cambridge entrance exam and go for interviews at the college I’ve applied for, which means my studying isn’t over, even though the A‑levels are. I’m still supposed to be reading art books, going to galleries and exhibitions, building up my knowledge as much as possible. So it’s very easy to tell my mother, over dinner, that I’m going to an exhibition at the Wallace Collection tomorrow with my friend Lily-Rose--paintings from the Castello di Vesperi in Chianti. Her eyes don’t even flicker; she forks up another piece of grilled chicken, smiles at me, and says that sounds lovely. No recognition of the name at all.

I test it out again, at the end of dinner, as I’m stacking the dishwasher; I mention the name of the fictitious exhibition again, and how much I’m looking forward to it.

“Goodness, you are keen!” Mum says. “You’ve been out at museums all this week!” She yawns. “Time to collapse on the sofa, don’t you think? What film shall we watch tonight?”

So that’s totally conclusive. No recognition of the name di Vesperi at all. Mum is the worst liar in the world, which is probably why her brief attempt at an acting career failed completely: she’s incapable of pretending to feel anything she doesn’t. It’s probably why she was such a good model, though. She’s as transparent as a pool of water; every new emotion is instantly registered on her face. We have some of her most famous photos hung in the flat, and I love them all, because they capture Mum’s expressions so perfectly--wistful, happy, thoughtful, loving. She told me once that photographers she worked with learned how to trigger her emotions: they’d yell “Think of cute puppies, Daisy!” if they wanted her to smile, or “Your boyfriend said he needs to take a break!” if they were after romantic melancholy.

And the most famous photo of all, the Vogue cover where she’s holding an orchid in her hand, staring at it with a misty, tender gaze in her big blue eyes, her blond hair falling down her back: in that one, she said, the photographer told her to look at the flower and think of what she loved most in the world.